The X Factor's total audience of 8.7 million viewers, a 42.4% share, was the worst for a launch show since 2006, while Ant and Dec game show Red or Black? lost out to another showing of Indiana Jones and the Kingdom of the Crystal Skull on BBC1.

With the hot weather presumably partly to blame, The X Factor – which aired on ITV1 between 8pm and 9.30pm on Saturday – was down from just over 11 million viewers last year and was the lowest launch audience since 7 million viewers (37%) watched the third series begin in 2006.

The ITV1 talent show is now into its second year without Cowell on the judging panel but has stuck broadly to the recipe of last year's show, with Nicole Scherzinger replacing Kelly Rowland among the judges.

Stripping out timeshifted channel ITV1+1, Saturday's The X Factor had 8.1 million viewers on ITV1, a 39.4% share, compared with last year's 10.5 million, 44.5% of the audience, on the main network.

The second series of controversial game show Red or Black?, which was wrapped around the return of the X Factor to give it as much of a ratings lift as possible, had 3.4 million viewers (20.5%) for its first instalment between 7.15pm and 8pm, and 4 million (19%) between 9.15pm and 10pm.

This was down on last year's first series which began with 6.6 million (30.8%) and 7.2 million (31%) for its results show.

The earlier edition of Red or Black? lost out to the BBC1 Harrison Ford movie repeat, Indiana Jones and the Kingdom of the Crystal Skull, which had 4 million viewers, a 24.6% share, between 6.25pm and 8.20pm.

Red or Black?'s results show was beaten by BBC1's Casualty, which averaged 4.2 million viewers (20.1%) between 9.10pm and 10pm.

Although Cowell is no longer on The X Factor judging panel, busy across the Atlantic making the US version for Fox, his company Syco TV co-produces both The X Factor, with Thames, and Red or Black?, which he makes with ITV Studios.

Saturday also saw the return of Jonathan Ross to ITV1's Saturday night schedule.

The Jonathan Ross Show had 3.6 million viewers, a 20.3% share, between 10pm and 11.10pm.

It was up against BBC1's Match of the Day, which returned on the first day of the new Premier League season and was also watched by 3.6 million viewers, a 23.9% share, between 10.20pm and 11.40pm.

Earlier, BBC1's Total Wipeout returned for its fifth and final series with 2.4 million viewers (19.4%) between 5.25pm and 6.25pm.

The X Factor: launch show ratings

2012: 8.1 million (39.4%), 8.7 million including ITV1+1

2011: 10.5 million (44.5%), 11 million including ITV1+1

2010: 11.1 million (47.8%)

2009: 9.9 million (48%)

2008: 10.2 million (48%)

2007: 9.5 million (45%)

2006: 7 million (37%)

2005: 6.7 million (41%)

2004: 4.9 million (26%)

(overnight audience, including ITV1+1 where stated)

All ratings are Barb overnight figures, including live, +1 (except for BBC and some other channels including Sky1) and same day timeshifted (recorded) viewing, but excluding on demand, or other – unless otherwise stated. Figures for BBC1, ITV1, Channel 4 and Channel 5 generally include ratings for their HD simulcast services, unless otherwise stated

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